Mechanical stoker.



HJSEBMAN.

MECHANICAL STOKER. APPLICATION FILED SEPT. 11', 1911,

Patented Jan. 19, 1915.

6 SHEETS-SHEET 1.

WITNESSES:

v H. ISERMAN. MECHANICAL STOKER.

APPLICATION FILED SEPT. 11, 1911.

6 SHEETS-SHEET 8.

I INVENTOR 7' (j? y I WITNESSES.

H. ISERMAN. 1150111111011 STOKER.

APE-1011:1011 FILED $1321.11, 1911.

Patented Jan, 19, 1915.

6' SHEETS-SHEET 5.

' ATTORNEY and State of To all whom itv may concern Be it known that I, HARVEY ISERMAN, a citizen of the United States, residing at New Hyde Park, in the county ,of Nassau New York, have invented a certain new and useful Improvement in Mechanical Stokers, of which the following is a full, clear, and exact description.

y invention relates to improvements in 10 mechanical stokers of the endless traveling grate type, incwhich the fuel, delivered at the front of tlie'fiu'nace through a hopper, is progressively fed rearward as combustion takes place.

he primary object of my invention is to produce more complete and efficient combustion of fuel than has hitherto been obtained and to, this end I provide an arranigement of parts by which ignition of the 0 fue takes place'at the exact position de-' sired, the resulting gases and free carbon being passed between two highly heated surfaces, namely the white hot bedof fuel "below and a highly heated ignition arch above. In devices of this character it isalso highly essential that the bed of fuel be of uniform depth in its entire breadth in order that combustion may proceed at the same rate throughout the breadth of the furnace and to attain this object I provide a novel furnace front and arch.

Another object of my invention is to provide a structure by which 'air is prevented from passing around the sides and ends of the grate where it cannot aid in the process of combustion, but on the contrary causes a loss in efliciency.

Another object of my invention is to provide a grate, the parts of which are simple to construct and replace, and which grate may be constructed of any desired width, thus accommodating it to furnaces of extreme breadth.

Further objects of my invention will here 5 inafter appear inthe specification and be pointed out in the appended claims.

In the accompanying drawings, Figure l is a view in central vertical cross-section showing the boiler and ash car in elevation 9 and showing the stoking mechanism and its supporting frame complete but with the fire-brick side closures removed, to more clearly disclose the frame. Fi'. 2 is a elevation of the furnace andstoker mechanism, with the fuel hopper removed,

Specification of Letters Patent.

the grate .bar adapted to my invention. Fig.

which rest upon the side walls and Patented Jan. '19, 1-915. Application filed. September 11, 1911.. fiortalfio. ,7425:

with one furnace door opened to'more clearly show its. construction and. with. a. part of broken away to show the: grate supports and blast p' Fig.2? is an em larged vertical sect on of the furnace and stoking mechanism, looking toward the rear of the furnace, taken on' the line :11 m Figs 1 and with the side closure. bricks in. position on the frame. Fig. 3' is a perspective of. the side plate, the tension device and the blast pipe. Fig. 4 is a detailof the tension. device.

Fig. 4 shows the special fire-brick side closure and its mounting on the frame. Fig. 5 is an isometric of the gear case, partially broken away to show the transmission. Fig. 6 is a perspective of the special fire-brick lining employed in the doors. Fig. 7 is a plan, broken away at each end, of a pair of grate bars. Fig. 8 is a side elevation of an end grate bar section and a portion of an intermediate grate bar section. an end view of the grate bar 7 and 8. Figs. 9 and 10 are to Figs. 7 and 8, of another Fig.

views, similar form of grate perspective of an end of the grate bar sectlon shown in Figs. 9 and 10, looking at it from the under side.

As shown in the drawings. 1 is a steam boiler mounted in the usual furnace structure which has side walls 2 and the front wall 3. The furnace is also provided withthe customary rear wall 4 having a bridge 5. The front of the furnace is covered by a metal plate 6 which extends down over the side walls, forming a covering therefor and a means of mounting the doors, hopper, side plates and other parts of the mechanism to be later described. Instead of the customary arch for carrying the side walls, the front wall. and such weight of the boiler and its contents as said front wall receives, I proi ide one or more structural iron or steel members 7. in this instance shown as steel T beams, which support the wall 3 and transmit thereto in the direction of their strength, that is vertically. This construction has a material advantage over either the flat or springing arch in that there is no 1lliorizontal thrust exerted against the side wa s.

I protect the lowerfaces of the member or members 7 from the heat of the fire by the brick 8 which are mounted on doors 9.

the load These doors, of which there are two, (one being open in Fig. 2) have a front plate 10 of sufficient width to cover that portion of the brick of front wall 3 below the front plate 6 and to extend down and. form the of the fuel as it passes from the hopper on to the grate.

. The doors are mounted on hinges 12, 13'

bolted thereto and provided with orifices to receive hinge pins 14, 15.bolted on the front plate 6. The hinge pin 15 is threaded and provided with a nut 16. By turning the nut 16 the position of the door may be vertically adjusted to adjust the space between the door 9 and the traveling grate. It will be understood,\of course. that the bricks 8 must to reach to and protect the metal parts 7.

be changed when the position of the doors is adjusted, to provide brick of proper siae The doors are shown in their highest position in Fig. 2. Supports 1210f adjustable length aid in carrying the Weight of the doors.

Water is supplied to the water cooled chambers 11 through pipe 17 and is drawn off through pipe 18. These pipes are provided with swivel connections 20. 21 to permit the opening and closing of the 'doors 9, and with flexible connections 22. 23 to permit of the vertical ad'iustment of the doors and the pipes carried thereby. I prefer to employ boiler feed water for cooling the doors thus preheating said feed water and increasing the eliiciencv of the boiler.

The tire brick 8. of which an, number may be employed but of which three are shown for each door, are provided with a shoulder 24 to .fit over the chamberll. and with apertures Q-l-l to receive bolts 25 having nuts 26 to fasten the brick to the front late of the door. After the brick are fassued in place the cavitv 27 may be filled with clay or like material. Grooves 130 in the sides of the brick 8 receive correspond" ing ridges 131 on adjacent brick. thus locking the brick more securely in position.

' The lower faces'of fire-brick 8 are beveled upwardly toward the rear giving a slight incline tothe ignition arch 100, as clearly shown in Figs. 1 and 6. It is through the narrow space between the fuel bed and this ignition arch 100 that the car bon and gases released on ignition must pass audit is here that'thev are consumed.

J fuel hopper 28 is removablv attached to the furnace front by inclined fingers 29 entering: cars 30 bolted to said front. Strap iron guides 31 attached tofithe outside of the hopper pass over the side plates 49 and aid in steadying andsupporting the hop per. Openings 32 are provided in the hopper sides to accommodate the water pipes 17 and 18.

The traveling grate is mounted in a frame whose side .elements are formed by flat standards 33, joined at the top by fiat horizontal members 3-): which extend out in.

front of the furnace a distance of about 3 feet and are received in grooves 35 (Fig. 3) in the journal boxes l8, and joined near the bottom by a horizontal member 36to each of which members the standards are riveted. The sideelements of the frame are ioined by upper shafts 37' and lower shafts 38 having long threads at each end and provided with nuts 39, 40 whereby the standards may be firmly'joined at adjustable distances as desired. The shafts 37 carry grooved idlers 41 journaled thereon, for supporting the upper run of the grate. Journaled on the lower shafts 38 are rollers 42 for supporting and cleaning the lower run of the grate. The chains 43, which carry the grate bars, and of which four are shown in the present instance, though any desired number may be employed, run on frontsprockets at and rear sprockets 45. The rear sprockets are mounted on a shaft 46 journaled in the frame. The shaft 47 which carries the front sprocket is journaled in boxes 48 which are slidably mounted in apertures in the side plates-49. The

boxes are notched at 50, 51 to engage the plate .49" and prevent lateral motion of the box. Angle irons. 5.. are riveted to the side plates with their upper surfaces in position for the under side of the boxes to rest thereon to afford a large bearing surface therefor.

Adjustment of the tension on the chains 43 is accomplished by means of a pair of screws 52 hearing in sockets 53 formed on the rear side of the iournal box. These screws are provided with nuts 5% which bear againstthe abutments 55 formed of two straps riveted one on each side of the plates 49 and each. shaped centrally to accommodate the tension adjustingscrew 52 but not large enough to recei e the nut 54. By turi iing the nuts to advance the screws 52 away from the furnace the tension on the chain 43 can be increased as desired.

The plate 49 is bolted to the furnace front 3 or steam to all points of that portion of the grate passing at a given time under the ignitinn arch. it is important thatthis pipe lea shall have its center under the front edge.

ofthe water cooled chamber ll in order that mamas a ignitionof the fuel may take place at prereadily understood that, by addin sections,

c sely the'right point, and to permit of this a grate bar of any desired lengt may be I provide an offset 57 therein. obtained. When, as is the case at the right In Figs. 7 to inclusive I have illusof Figs. 8 and 10 the section is to an end trated two types of grate bars, the abutting one, the upper leg of a vertical link of a and inter-meshing, and have illustrated the chain 3is placed in the notch 62 and a bolt manner of forming said bars of bar sec '64 is passed through the vertical link and tions and of fastening them to the chains. the lugs 63 and 631 and fastened in place contemplated by my invention. While I b any suitable means, as a cotter pm 65. have. only illustrated these two designs of ig. 8). If, as shown at thcleft hand side 76 I rat bars. I do not limit myself to them, of Figs. 8 and 10, the chain is one of the inhaving merely selected them for purposes of termediate ones, it .is joined to the sections illustration. These bars are however in at their juncture. ,A vert cal chain link fits themselves of a type broadly. new. Like in the opening formed by two half-notches numerals refer to corresponding parts on 621 and the bolt 641 is received in lugs 631, 80 both illustrations and, for convenience, both one onzeach grate bar section. If desired to forms will be described at the same time. ive stiffness, longer bolts may be used and As previously stated the grate structure they may ass through one or both lugs 63. is carried on endless conveyer chains 43. I prefer, owever, to make the bolts 641 Each grate bar 57 is composed of a pluthe same as bolts 64 so that one style may be rality of grate bar sections, a, b; c, in the used in. both places. present instance three, though it will be One end of each grate bar section bears a readily understood that as many sections as projecting integral pin 58 and a recess 59, desired may be employed, thus adapting my shaped to fit a pin 58, is formed in the other device to furnaces of any width. All grate end of the bar section. When the sections bar sections are exactly alike, each being cast are assembled, a pin 58 fits in a recess 59 in with a pin 58 on one end and a socket 5,9'on the next adjoining section, thus adding'stifi' the other. Each section is formed with a ness to the rate bar. I prefer to knock offweb 60. The type of grate bar illustrated in the pin 58 rom the end section of the grate, Figs. 7, 8 and 8 has oppositely placed teeth thus giving a closer fit between the grate 601', while that shown in Figs. 9, 10 and 10 and the side closure. is provided with staggered teeth which in- My improved grate bar section may be determesh with the teeth of the next adjacent scribed in general terms as provided 'at each grate bars, thus forming a self cleaning end with dual attaching means, the one for grate. Each grate bar section is provided use when the section is to be attached to an a of any suitable shape to permit of the use In order to back up the ash and partial at each end with a half-notch 621 and adoutside chain or other flexible conveyer, and jacent each end with a full notch 62. The the other for use when the section is to be notches 62, or a pair of half-notches 621, attached to an intermediate conveyer; when two bar sections are joined end to end, The fuel bed decreases in thickness from form an opening of suchdimensions to front to rear due to consumption of the easily receive the upper leg of a vertical link coal and it is of importance that it should of a chain 43. These notches are shown as not become too thin at the rear for the reabeing rectangular in cross section but it son that an excess of air would then pass up will be readily understood that they may be through it, resulting in a loss of etliciencjy.

y 1.1 stated. Adjacent each endof each grate consumed fuel and also to reduce as much bar section, and between half-notches 621 as possible the opening for the passage of and notch 62, are lugs 631 which, shown in air behind the rate, Lprovide a retardin Figs. 7, 8 and 8, are formed by continuing plate or bridge 0, shown in Figs. 1 and 2 a pair of teeth on the same "bevel to a dis- This retarding plate as illustrated, is a holtance of about two inches below the Web; in low water cooled one, made of boiler plate the type illustrated in Figs. 9, 10 and 10 and rigidly mounted on a plate 71 secured the lugs 63 are asymmetric, being formed by by angles to the top of the front plate 72 of the extension 'of the web and one tooth only. the ash chamber. Cooling water is admitted Similar lugs 63 are formed on the sides of to the hollow retarding plate 70 through .2 notches 62 toward. the, middle of the bar pipe 73 and drawn off through pipe 74. The and at like distances from said notches. The heated water from pipe 74 may, if desired,

- lug 631 is located from the end of the bar at be used in feeding the boiler. The ashes a distance equal to half the distance between pass up over plate 70 and fall down into a lugs 63 and 631. Bolt 632 are formed, chamber, the front wal}ll of which is'plate 72 preferably by drllling," 1n the lugs ,63 and the back Wall of w ich is formed by the and 631. i f furnace bridge wall 4. Inclined plates 75 In Figs. 8 and 10 I. have shown only the riveted to angles 76 bolted to the wall 4, it hand bar s'ectionand a portion of one' form the side walls of the ash chamber. of the intermediate se tl ns. ut it w l be he 962 o haash hamber is...o n y 1.3.0

anism derives its power from line shaft 81 carrying eccentric 82 which communicates reciprocatory motion to the eccentric rod 83. The eccentric'rod is attached by slot and pin connections 84 to the ratchet 85 which engages ratchet wheel 86. The ratchet wheel 86 is rigidly attached to the worm shaft 87,

(see Fig. 5), mounted in they housing 88, which fits over the front sprocket shaft 47 on the outside qr one of the plates 49. This housing fits loosely on shaft 47 and is held in position by collars 89 thereon. Rollers 90 mounted between the side plates. of the housing carry its weight to the floor. On the worm sha-ft"87,is the worm 91 which engages the gear wheel 92 keyed to the sprocket shaft and inclosed in the housing 88. Through these connections power 1s transmitted from the shaft 81 to the sproclcet shaft 47 to move the grate.

By changing the position of the-pin connection 84 in its slot the throw of the ratchet 85 may be adjusted thus controlling the number of teeth of the wheel 86 engaged by the pawl and the angle through which the gear 92 is rotated. In this manner the speed of travel of the grate may be regulated as desired. H

I have shown and described the actuating mechanism as being applied to one end of the shaft 4:7 only but I may, if desired,

duplicate this mechanism of the grate. I In Figs. 2 and r is shown ,a special fire-brick closure 93 grooved at 94 'toI-receive the side member 34 on which it .rests and is supported. The closure is slightlyat the other end shorter on the side 95 and is of just suiiia. cient height above grate 57 to clearsaid This closure prevents air from pass-; ing up around the side of the grate and fuel" grate.

from falling down in the space" between the grate and the frame.

As previously stated, the position'ofthe blast pipe 55 is ofgreat importance as it is 50- located that ignition of the coal "takes place soon as it passes under the water cooled chamber'11'.' The fine particles of free carbon, hydro-carbons and carbon monoxrd, liberated in the first stageszof combustion, are thus compelled to pass through the constricted passage between the highly heated ignition arch 100 and the glowing bed of fuel below. At the temperatiire tp which they are thus subjected I the gases and free carbon are totally oxidized, due to the excess of oxygen from the blast, and all the high heat units derived from such complete combustion are thus utilized. Unless the gases which are 'initially freed from the fuel are passed through sucha highly heated oxidizing zone and in contact above and below with incandescent surfaces, alarge percentage of valuable gasespasses up the stack without ever being completely oxidized.

In deyices of this character it is highly essential that the bed of fuel be of uniform depth in its entire breadth in order that combustion may proceed at the same rate' throughout the breadth of the furnace. This cannot be secured with a springing arch even though other devices to spreadthe fuel be employed. With the forms of flat arches heretofore employed successful results could'notbe obtained for the reason that the side Walls are not sufficiently strong to withstand the lateral thrust of a longfiat arch in which the stresses are largely horizontal, and also for the reason. that in such arches the bricks will 'work loose through repeated heating and cooling. The combination of a flat arch supported on struc tural iron beams. with the beams protected from} the fire, obviates the objections noted above to both the springing and flat arches, and the doors, aside from providing a convenient means of protecting the flat arch, furnish convenient access to-the interior of the furnace for purposes of repair or firing.

In the specification and claims I have, for the want of a more descriptive word, referred to the cut out portions 621. as halfnotches. By this term I intend to specify a recess, open'on two sides, whichrecess alone "ilS not sufliciently large to receive a link of aconveyer chain but which will coiiperate with a similarrecess on an abutting section to form a recess of approximately the same size as the notches 62 and, like said notches 62, capable of receiving a'liiik of a conveyer chain. The claims shouldbe construed in view of thelimitations given the term -halfnotches in this paragraph.

. I-lavingthusidescribed my invention, what ta'ching' the section tofa conveyer and ele.-.

ments of anatt'aching means adapted, to 'co operate with similar elements on an ad-,

iacen't section, the first attaching means he ate conveyer. v

A grate bar section provided on its lower surface at eachend W1th a half-notch,

An interchangeable grate b'ar section] provided near each end with means for at- 30 may be desired.

a lug, a full notch/and a lug, arranged in the order named from the end toward the middle of the grate bar section, the full notch being midway between the lugs and the first named lug being midway between i the full notch and the half-notch, the arfirangementof lugs and notches being such that each end of said section is adapted for,

' connection to a carrier member alone, or for it) interchangeable connection to a icarrier member and another section of the same description.

3; A" grate bar section provided on its lower surface at each end 'with'a half-notch,

5 a lug, a'full notch and a lug, arranged in the order named from the end toward the middle of the grate bar section, the arrange ment of lugs and notches beingsuch that each end of said section is adapted for connection to a carrier member alone, or for interchangeable connection to a carrier memher and another section of the same description.

4. A grate bar section provided on its lower surface at each end with a half-notch and adjacent each end with a full notch, whereby a grate bar section may be joined to a chain adjacent the end of said section or at the juncture between two bar sections, as

In an endless traveling grate, the combination of a plurality of endless conveyor chains, with gratebars mounted transversely thereon, each grateba-r being composed of ,a plurality of grate bar sections joined end to end, each grate barsection having at each end a half-notch, a lug, a full notch and a lug, arranged from the end toward the middle of the bar section in the order named,

40 whereby each grate bar section is ada ted to be used either as an end or an interme iate section, the chains and bar sections being so relatively located that the side chains are received into the notches adjacent the ends of the grate bar sections and that the intermediate chains are receiged into the space formed by two half-notches at the juncture of thegrate bar sections, pins passing 7 through the vertical links of the chains and through the adjacent lugs and means for holding the pins in' position.

6. In a mechanical stoker, a traveling grate supported by a suitable frame, and actuating mechan sm for said grate comprising a power shaft, an eccentric thereon,

as eccentr c ro d' receiving reciprocatory mot on from saidshaft," pawl and ratchet mechanism adjustably connected with said eccem tric rod, a worm shaft upon which said ratchet is mounted, an adjustable sprocket shaft, a worm on the worm shaft, a gear wheel mounted o the sprocket shaft and engaging the worm, and a housing movable relative to said frame loosely mounted on the sprocket shaft, said housing carrying saidworm shaft and protecting said worm and gear.

7. In a mechanical stoker, a traveling grate supported by a suitable frame, and ac tuating mechanism for said grate comprising an adjustable sprocket shaft, a gear on said shaft, a worm shaft, means for rotating said worm shaft, a worm on said worm shaft engaging said gear, and a housing movable relative to said frame mounted on said sprocket shaft, said housing forming a mounting. for said worm shaft and a pro tection for said worm and gear.

8. In a mechanical stoker, a traveling grate supported by a suitable frame, and actuating mechanism therefor comprising an adjustable sprocket shaft, 9. gear on said shaft, a worm shaft, means for rotating said worm shaft, a worm on said worm shaft engaging said gear, and a housing movable relative to said framc'niounted. on said sprocket shaft and supported on the door, said housing forming a mountingfor said worm shaft and a protection for said worm and gear.

9. ha mechanical stoker, a traveling grate, a frame in which said grate is mounted, in combination with wide closure brick a slotted to receive the side members of the franie'in such manner as to be supported thereon, said closure brick being shaped to project over the grate and to close the opening between the grate and the furnace wall.

10. In a mechanical stoker, a traveling grate, a frame in which said grate is mounted, in combination with side closure bricks slotted to receive the side members of the frame in such manner as to be supportedv thereon, said closure brick being shaped to close the space between the frame and a fur nace wall and to project over the grate in close proximity thereto.

In testimony whereof, I hereunto allix my signature in the presence of two witnesses.

HARVEY 'ISERMAN.

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